Cerebellum Flashcards
what are the roles of the cerebellum?
comparator and coordinator
motor sequencing
postural control
the cerebellum as comparator and coordinator
compares desired outcome of movement to what’s actually happening
makes adjustments on the fly
can coordinate muscle activities (ie. head movement w/eye movement)
what does the motor sequencing role of the cerebellum involve?
can link outputs together
what does the postural control role of the cerebellum involve?
anticipatory movements
stabilize the proximal to move the distal
what are the cerebellar tracts?
rubrospinal and reticulospinal-BS
vestibulospinal-vestibular system
spinocerebellar-SC
does the cerebellum have any direct connections to the lower motor neuron pool?
no, the cerebellum has no direct connections to LMNs, so damage to the cerebellum wouldn’t result in deficits to muscle strength
what is feedforward control?
get information from previous experiences
no way to correct errors in output
quick
no true feedforward systems in the body
what is feedback control?
sampling the environment causes change
info fed into comparator to see differences b/w desired and output info
error signal will change the output
accurate
not as quick bc it requires constant adjustments
where is the vermis in the cerebellum?
in the midline
what does the primary fissure separate?
the anterior and posterior lobes
where is the paravermis?
lateral to the vermis
where are the lateral hemispheres?
lateral to the paravermis
most lateral aspect
what is the floculonodular lobe?
the combination of the flocculus and nodule
what structures does the vermis contribute to?
head neck and trunk
what structures does the paravermis contribute to?
limbs
what structures do the lateral hemispheres contribute to?
digits (fine motor control)
what are the 3 nuclei in the cerebellum?
fastigial nucleus
intermediate/interposed nucleus
dentate nucleus
what is the fastigial nucleus?
the most medial cerebellar nucleus
receives input from vermis and cerebellar afferents that carry info from vestibular structures
what is the intermediate/interposed nucleus?
lateral to the fastigial nucleus
input from paravermis and cerebellar afferents that carry spinal and visual info and somatosensory info
what is the dentate nucleus?
the most lateral cerebellar nucleus
receives info from lateral hemispheres and cerebrum
what are the inputs of the cerebellum?
mossy and climbing fibers
are the inputs of the cerebellum (mossy and climbing fibers) excitatory or inhibitory?
excitatory
what are the outputs of the cerebellum?
Purkinjie cells
- project to cerebellar and vestibular nuclei
are the cerebellar outputs (Purkinjie cells) excitatory or inhibitory?
inhibitory (GABAergic)
what are the only efferents going out of the cerebellum?
the 3 cerebellar nuclei (dentate, interposed, and fastigial)
what fibers provide the error signal?
climbing fibers
superior peduncle
major efferent pathway connects to the midbrain
- does have one afferent tract
from deep nuclei of cerebellum to thalamic nuclei (and to cerebral cortex) and red nuclei
middle peduncle
major afferent pathway connects to the pons
from cerebral cortex via pontine nuclei
largest peduncle
inferior peduncle
afferent and efferent pathways
connects to medulla
afferents coming from from SC (proprioceptive info) vestibular apparatus and nuclei ipsilaterally
efferents go back to vestibular nuclei and reticular formation
vestibulospinal and reticulospinal
what are the functional divisions of the cerebellum?
vestibulocerebellum
spincerebellum
cerebrocerebellum
what is the vestibulocerebellum division?
input: vestibular apparatus
output: vestibular nuclei
- eye movements and balance/equilibrium
folculonodular lobe
efferents from fastigial nucleus
vestibulocerebellar tract projects vestibular info to vermis (adjustments to posture) and floculonodular lobe
out of inferior peduncle
vermis to contralateral fastigial nucleus to ipsilateral vestibular nuclei (double decussation)
mostly ipsilateral bc of double decussation
what is the spinocerebellum division?
input: somatosensory, visual, auditory, vestibular
output: lateral corticospinal and corticobrainstem tracts and medial motor tracts
anticipatory, corrective, and responsive adjustments to movement
vermis and paravermis-efferents out of vestigial and interposed nuclei
high fidelity pathways and internal feedback pathways
ipsilateral projections
info from superior peduncle
vermis projects to medial motor tracts
paravermis projects to reticulospinal tracts
interposed nucleus to red nucleus
what are the high fidelity pathways?
posterior spinocerebellar and cuneocerebellar
high accuracy of how things are moving in the body
what are the internal feedback pathways?
anterior spinocerebellar and rostrospinocerebellar tracts
not conscious level info
rubrospinal
controls flexors
what is the cerebrocerebellum division?
input: somatosensory, visual, auditory, vestibular
output: cerebral cortex, lateral corticospinal and corticobrainstem tracts
fine, distal voluntary movements and no motor emotional controls
movement planning-timing
afferents: cerebral cortex via pontine nucleus
vermis, paravermis, and lateral hemispheres
closed loop
double decussation-ipsilateral
cognitive functions: goal-directed behavior, language optimization, visuospatial function
emotional and social functions: emotional memories and social behavior
cerebellum–>cortex–>cerebellum
dentate–>red–>motor areas
what 3 arteries make up the vascular supply of the cerebellum?
superior cerebellar artery (SCA)
anterior inferior cerebellar artery (AICA)
posterior inferior cerebellar artery (PICA)
what is the superior cerebellar artery a branch of?
the basilar artery
what is the anterior inferior cerebellar artery a branch of?
it is a lower branch of the basilar artery
what does the anterior inferior cerebellar artery supply?
flocculus and middle cerebellar peduncle
what is the posterior inferior cerebellar artery a branch of?
the vertebral artery
what occurs in cerebellar dysfunction?
it effects postural control, automatic movement, eye movement, and voluntary movement
has cognitive and emotional effects
unilateral lesions affect the ipsilateral side of the body (w/one exception)
